1. Field of the Invention
The present invention relates to an electronic apparatus on which a portable storage medium can be detachably mounted and which is adapted to be used with the portable storage medium being mounted, and more particularly to an electronic apparatus utilizing a portable storage medium for preventing resonance generated by the configuration or construction of a metal plate or the like on an insertion face of a unit into which a portable storage medium, such as a magnetic disk, an optical disk or a magneto-optical disk, is inserted for use when radio waves are generated outside the unit or equipment in which the unit is installed to thereby prevent, in turn, a malfunction of the unit.
In recent years, portable electronic equipment and portable radio equipment have become common, and there has been a growing tendency that both are used, simultaneously, in a closed environment. As a result of this, there can occur a case where a strong electro-magnetic field is applied from the radio equipment to the electronic equipment in which a portable storage medium is installed. When this happens, the peripheral portion of the equipment which surrounds the installed portable storage medium may resonate, and the level of electro-magnetic field is increased,.whereby the read circuit or the like of the electronic equipment is caused to malfunction.
As countermeasures against the malfunction described above, there has been a demand for an increase in resistance to electromagnetic fields by configuring and/or constructing the metal plate on the insertion face where the portable storage medium is inserted or a metal plate at the mounting portion of the unit such that they do not resonate even when affected by radio waves or by modifying the distribution of electro-magnetic field inside the unit.
2. Description of the Related Art
Conventionally, since no countermeasures against electro-magnetic fields have been taken in considering the size of a metal plate constituting the insertion face for a portable storage medium, there has been a problem that the metal plate resonates with radio waves generated outside, whereby the electro-magnetic field of the radio waves is increased to thereby cause the read circuit of a unit using a portable storage medium to malfunction.
As an example, a theoretical case will be described in which resonance occurs. Resonance by radio waves is generated when the length of a conductor or the size of frontage becomes a half the wave lenght (xcex) of the radio waves or a multiple of an integer number of the wave lenght. For example assuming that size of the portable storage medium insertion face is 1xc3x9710 cm and that the frequency (f) of an radio wave is 1.5 GHz, then the wave length of the electronic radio wave is obtained from the following representation:
Wave length xcex(m)=C/fxe2x80x83xe2x80x83(1);
Where,
C is the velocity of light, 3xc3x97108 (m/s)
f is frequency (Hz)
and if the actual numerals are substituted for those in the representation (1),
Wave length xcex=3xc3x97108/1.5xc3x97109=0.2 m(20 cm)xe2x80x83xe2x80x83(2)
Therefore, one half the wave length xcex is 10 cm, and since this coincides with the longitudinal size of the portable storage medium insertion face in the conventional apparatus, resonance may be generated to cause a malfunction of the apparatus.
As is described above, conventionally, there was a risk that resonance is generated by the configuration or construction of the metal plate or the like on the portable storage medium insertion face, whereby the electro-magnetic field strength of the radio wave is increased, resulting in a malfunction of the unit using the portable storage medium.
With a view to solving the aforesaid problem, an object of the present invention is to provide an electronic apparatus utilizing a portable storage medium which has is constructed to absorb radio waves and improving its resistance, a construction for improving the yield strength for accommodating a unit or a construction for configuring a metal plate or the like on a portable storage medium insertion surface such that no resonance is generated.
With a view to attaining the aforesaid object, according to the present invention, there is provided an electronic apparatus, adapted to be used with a portable storage medium being installed therein, utilizing a portable storage medium characterized in that a metal plate or the like on a portable storage medium insertion face is configured or constructed such that the metal plate or the like does not resonate with radio waves generated outside the apparatus.
In this case, the size of the metal plate or the like on the portable storage medium insertion face is selected such that the size does not have a xc2xdxcex, xc2xcxcex, . . . relation or a multiple of an integer number relation to the wave length(xcex) of the radio waves.
In addition, according to the present invention, there is provided in an electronic apparatus in which a portable storage medium is removably installed, and which is adapted to be used with the portable storage medium being installed therein, utilizing a portable-storage medium characterized by a construction in which a mounting portion where a unit for driving a portable storage medium is mounted is constituted by a metal plate and in which, when a storage medium is installed, an opening in the metal plate into which the storage medium is inserted is electrically connected between an upper portion and a lower portion thereof, so that the metal plate does not resonate with radio waves generated outside.
In this case, flexible flaps are provided at the upper and lower portions of the opening in the metal plate so that the flaps and the metal plate are brought into electrical contact with each other.
In addition, according to the present invention, there is provided, in an electronic apparatus adapted to be used with a portable storage medium being installed therein, an apparatus for utilizing a portable storage medium characterized by a construction in which a mounting portion where a unit for driving a portable storage medium is mounted is constituted by a metal plate, and in which upper and lower portions of a rearward metal plate are connected to each other and are situated on an opposite side to the side where the storage medium is inserted, so that the metal plate does not resonate with radio waves generated outside.